1. Field of the Invention
The present invention relates to an ultrasonic diagnostic apparatus and, more particularly, to an ultrasonic diagnostic apparatus that provides an ultrasound image having improved image quality through efficient filtering and image synthesis.
2. Description of the Related Art
An ultrasonic diagnostic apparatus has non-invasive and non-destructive characteristics, and is thus widely used in a medical field to obtain information about the interior of a diagnosis target. The ultrasonic diagnostic apparatus can provide a real-time high-definition image of internal tissue of a human body to a doctor without surgical operation entailing direct incision and observation of the human body, and is thus very important in the field of medicine.
The ultrasonic diagnostic apparatus electrically stimulates conversion elements to generate an ultrasound signal and transmits the generated ultrasound signal to a human body. The ultrasound signal is reflected as an ultrasound echo-signal at a boundary between discontinuous human tissues, and the ultrasound echo-signal transmitted to the conversion elements from the boundary between the human tissues is converted into an electrical signal. The ultrasonic diagnostic apparatus amplifies and signal-processes the converted electrical signal to generate ultrasound image data about the human tissue.
Generally, the ultrasonic diagnostic apparatus performs filtering of ultrasound image data using a filtering mask to remove various noise and obtain a clear image when forming the ultrasound image of each part of the body.
Meanwhile, conventional ultrasonic diagnostic apparatuses have a specific kind of filtering mask defined for use with each part of the body, for example, the liver, kidney, pancreas, heart, and the like. Accordingly, in the case of the kidney, the conventional ultrasonic diagnostic apparatus performs filtering upon ultrasound image data of the kidney using a single pre-designated filtering mask so as to obtain an overall ultrasound image of the kidney, as shown in a right side of FIG. 1. For reference, FIG. 1 comparatively shows a schematic diagram (left side) of an actual kidney and an ultrasound image (right side) of the kidney generated by the conventional ultrasonic diagnostic apparatus.
Conventionally, since filtering is performed corresponding to a blood vessel having a size of a specific range, as shown in the right side of FIG. 1, it is possible to obtain a relatively clear image of the blood vessel having a size or thickness greater than a certain value in the generated ultrasound image, but the filtering is not appropriately achieved for a blood vessel having a size or thickness smaller than the certain value, causing several small blood vessels adjacent to each other to be displayed in a superimposed state, so that the small blood vessels are not clearly displayed individually.
That is, the conventional ultrasonic diagnostic apparatus provides a mixed image of a clearly displayed portion and an unclearly displayed portion depending on the size or position of each of the body parts, particularly, the blood vessel, and the like. In order to make the unclearly displayed portion clear, there is an inconvenience to reset the filtering mask so as to match with the size of the blood vessel, and the like. Furthermore, in such a case, there is a problem that the existing clearly displayed portion is not appropriately filtered and becomes unclear.